A few months ago, after posting the above image on Twitter, I was contacted by Natalie Sopinka, who writes for the "Back Page" section of the American Fisheries Society's magazine (Fisheries) to share the story behind this photograph. You can find the full-text of the article at this link. Here, I wanted to share a few additional photographs about what it's like to work in the intertidal after dark.​

What are the conditions like at night compared to daytime?Working the night-tide is a visceral experience. As the sun slowly sets and your eyes adjust to the limited scope that your headlamp provides, a new practice of fieldwork emerges. You listen for the pulse of the waves in case one sweeps up closer than is safe. You scan the horizon with the scant headlamp aura, searching for familiarity in the dark ridges of the looming mussel beds. The ever-present mist and rain limit visibility further, so your other senses must take center stage. You crouch close to the ground to lower your center of gravity as you walk, because now you can’t discern villainous, slippery algae from bare rock. You scrabble on your hands and knees, feeling for the bolts that mark a permanent survey plot, and rummaging through blades of algae as you might rifle through a stack of papers. Perhaps the dark always acts to make humans feel alone, but it’s a much more solitary experience working the night-tide and in the silence I always have to remember to lift my eyes from my work to admire the unearthly landscape and smattering of stars.

As the sun sets, it becomes exponentially more difficult to get work done, so we often arrive at a site hours early, waiting for the first chance to work as the tide "goes out". Ideally, the most difficult tasks are done in the remaining light, however dim. For example, above, we are counting thousands of tiny mussels and barnacles on the rock within the white PVC square "quadrats". We use quadrats to make sure we always are counting plants and animals in the same sized area - a square quarter-meter. This way, all of our data are comparable.

Getting darker and darker.

Sun, moon, and planets at dusk over the intertidal. The far-off light on the horizon is from a boat, likely folks fishing late into the evening.

We use high-powered headlamps to work at night, each of us often wearing more than one headlamp and using additional flashlights if we have to take photographs. We work in pairs for safety in the dark. On wavy days, one person will work while the other stands looking out for sneaker waves.

The dark emerges & we keep working.

The tools of the trade: PVC pipes, waterproof cameras, rulers, pencils & Rite in the Rain paper, headlamps and our trusty brightly colored "foulies"PVC pipes (left) can be easily assembled (and disassembled) into a stable frame to hold a camera - especially at night when the dim light means camera shutter is open for longer and thus the camera must be very still to capture a clear picture. We often take pictures (center) in standardized ways (with a ruler, or with a consistently sized plot) to speed up the fieldwork process. Take pictures now - analyze later! (right) Headlamp illuminates a clipboard of waterproof paper, our datasheets.

A gunnel hiding under a blade of kelp, in the damp, cool coralline algae understory.

Animals in the dark(clockwise from top left) Pycnopodia helianthoides, a limpet cruises across a nice bare rock, a field of purple sea urchins, and Henricia leviuscula amid the urchins